Implementation of a Generalized Actuator Disk Wind Turbine Model into the Weather Research and Forecasting Model for Large-Eddy Simulation

A generalized actuator disk (GAD) wind turbine parameterization designed for large-eddy simulation (LES) applications was implemented into the Weather Research and Forecasting (WRF) model to enable numerical investigation of interactions between operating wind turbines and atmospheric boundary layer flows under a wide range of atmospheric conditions. Initial validation of WRF-LES with the GAD was performed using data from the Turbine Wake and Inflow Characterization Study (TWICS-2011), which measured flow properties in the vicinity of a 2.3-MW wind turbine. A fine LES containing the GAD was nested one-way within a coarser bounding LES, the latter using periodic boundary conditions to provide turbulent inflow for the nested domain. The simulations produced good agreement with observations at both upstream and downstream locations, including wakes with physically consistent rotation and velocity deficits that compared well with measurements from Doppler lidar scans. Two surface heat flux values of 20 W m-2 and 100 W m-2 were used to examine the sensitivity of the simulated wakes to atmospheric stability. While simulations using the smaller heat flux showed good agreement with wake deficits, those using the larger value showed enhanced spreading and more-rapid attenuation. This study demonstrates the utility of the GAD combined with atmospheric LES to potentially address a wide range of atmospheric science and engineering applications related to the interaction of wind turbines with the atmosphere and surface under increasingly realistic forcing.

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-649235